Tongue and slot connection between sheet material members



y 2- E. M. BROGDEN 2,289,824

'TONGUE AND SLUT CONNECTION BETWEEN SHEET MATERIAL MEMBERS "Filed No v. 12, 1938 INVENTOR ErnesT M. Brogden AII'TORNEY Patented July 14, 1942 UNITED STATES PATENT OFFICE TGNGUE AND SLOT CONNECTION BETWEEN SHEET MATERIAL MEMBERS Application November 12, 1938, Serial No. 240,167

8 Claims.

This invention relates to improvements in tongue and slot connections between sheet material members, and is particularly directed to an arrangement suitable for construction from paperboard and similar fibrous material employed in the manufacture of containers. It is especially adapted for use in mounting upon a container made of such material a handle constructed of similar material.

The provision of a handle on containers packed With small quantities of merchandise, intended to be carried by the retail purchaser and frequently referred to as consumer units, is of substantial commercial advantage; but the necessity for combining extremely low handle cost per unit with ample strength and convenience presents a difficult problem. Handles made of paperboard and the like meet the low cost requirement, but are readily distorted. and ruptured unless specially constructed, arranged and mounted to prevent damaging stresses.

The general object of the invention is to provide a separable connection of the tongue and slot type suitable for joining members such as a handle and a container made of sheet material and particularly of material of the paperboard type, which connection will have improved strength and resistance to rupture. Another purpose is the provision of an improved arrangement of this type that can be rapidly and readily assembled.

Such connections are generally provided with a tongue engaging a wall of the slot at two spaced points, usually adjacent the lateral margins of the tongue. A specific feature of this invention is the provision of integral slot-engaging means on the tongue located intermediate the side margins of the latter. This is accomplished in one embodiment by deflecting intermediate portions of the tongue out of the general plane of the tongue and into position for engagement with the slot margin; and the deflected portions may advantageously be held in operative position by engagement of the lateral edges of the tongue with the ends of the slot. A further feature of this construction is an arrangement whereby the deflected portions of the tongue may be flattened when the tongue is pushed through the slot beyond its operative slot-engaging position, as in collapsing the handle against the container, an arrangement that facilitates packing of the parts in superposed flat position. In a desirable form said portions of the tongue may be again deflected into operative position simply by drawing the tongue outwardly through the slot.

The deflected portions of the tongue may be connected to each other and integral with the tongue, or they may be separate from each other. In the latter arrangement the tongue may include spaced barbed sections each engaging a separate slot; and a feature of the invention is the arrangement of these slots to provide for convenient and rapid insertion of the tongue sections without distortion of the barbs, and positive retention of the inserted portions in the slots after assembly. 'This arrangement includes specifically a construction whereby the tongue sections are inserted in separate slots by slight distortion of the sections from the normal plane of the tongue and when released they return to said plane to provide a positive lock between the tongue end and the slot means.

Tongue and slot connections usually include projections or recesses at the side margins of the tongue adapted to engage a margin of the slot, thereby providing two points of engagement. A feature of the invention is the provision of a structure having four bearing points on the same tongue, thereby so distributing stresses in a unitary tongue-and-slot connection as greatlyv to reduce the tendency of the sheet material to shear or tear at the points of slot-edge engagement or interlocking. This in general is advantageously accomplished by combining the slot-engaging structure intermediate the sides of the tongue with slot-engaging means located at such sides. Since in containers and handles made of sheet material of the indicated type the connections between the handle ends and the container body are ordinarily the weakest points in the container structure and determine the quality and cost of the material that must be employed, the reduction of the stress to which the material at any one such point is subjected, made possible by the present invention, is equivalent, for a given sheet material, to an increase in effective strength. This frequently permits constructing a container body having ample strength for the intended purpose from lighter or less expensive material than would otherwise be required; while the handle may be made of the same material as the body or, a may sometimes be advisable, of heavier or higher grade material. In either case, there is resultant economy in manufacture, not to mention other advantages.

Connections of the tongue-and-slot type are generally assembled by hand, and an important characteristic of such a connection embodying the principles of the invention is the ease and speed with which the parts can be put together. Provision is also made for holding the engaging parts in operative position, and particularly for utilizing the normal longitudinal stress on the handle or other tongue member to accomplish this purpose.

Other objects, advantages and desirable features of theinvention will appear from the following description considered in connection with the accompanying drawing in which,

Fig. 1 is a perspective view of an arrangement embodying the invention, including the upper portion of a container with a handle connected thereto;

Fig. 2 is a plan View of a blank for forming the handle shown in Fig. 1;

Fig. 3 is a fragmentary view from the inside of the container in Fig. 1 showing the handle end connection structure in collapsed position;

Fig. 4 is a similar View with the connection in operative position;

Fig. 9 is a fragmentary perspective View from the outside of the container showing a modified form of connection; and

Fig. 10 is a similar View of another modification.

The invention is applicable to a variety of sheet material structures in which two members are connected by inserting a tongue carried by one member through a slot in the other, with means on the tongue engaging the slot to prevent retraction of the tongue when subjected to normal tension. An example of structures of this type is provided by sheet material containers to which handles of sheet material are attached in the indicated manner; and the invention is illustrated in connection with an arrangement of this type. Various forms of container may be employed, as well as different handle constructions; but the invention is particularly applicable to arrangements in which the handle end connections are sufiiciently spaced and arranged on the container so that use of the handle will subject such connections to tension in line with the body of the handle and the subjacent portions of the container walls, without substantial transverse stress.

These conditions are provided when the handle ends are connected to opposite side walls of the container, an arrangement illustrated in Fig. 1. In this embodiment the handle 2| is formed from fibrous sheet material of the type indicated, and may be cut out integrally at a single operation. It includes a shank or grasping portion 22 and ends 23. Each end is formed as a locking tongue adapted to be inserted in a slot 24 (a simple transverse rectilinear cut or incision, in this instance) in container body 25, preferably made of similar fibrous sheet material, and interlocked with the slotted container wall in a manner to be more fully described presently. Slots 24 may advantageously be located in opposite sides 26 of the container body 25, and in any event are sufiiciently spaced so that when handle 2| is in use the stress on the handle and the container body slots 24 will be in the nature of tension except at the points of slot engagement, though it may include an inward component pressing the container against the merchandise packed therein and resisted by such merchandise, thereby maintaining the parts in tension.

As illustrated in Figs. 1 and 2, each handle end or tongue is in effect bifurcated, being 10ngitudinally divided by elongated triangular cut-out 3| into two sections or subtongues 32 each provided near its outer end with a barb 33 projecting from a side edge 34 and arranged for interlocking engagement with the upper edge of slot 24 at an end thereof. The tongue sections are provided with further locking means. In the present example, this is accomplished by means of a deflectable connecting web or strip of the sheet material left at the base of the aforesaid triangular out. As here shown this web is divided into two parts 21, hinged to the respective sections 32 along bending lines 28, and to each other along bending line 29. While these bending lines may be of various types, the described arrangement may be conveniently constructed by providing bending lines 28 in the form of creases projecting toward the outer face of handle end 23, and bending line 29 may be a score cut partly through the material from the inner face of handle end 23, a construction which is readily formed by a single die operation and which causes web 21 to be deflected in the proper direction when the sections of the handle tongue 23 are pressed toward each other.

The web 21, together with the characteristic properties of the sheet material employed, thus permit-s limited movement of the tongue sections toward and away from each other in the plane of the sheet; and they are of course also capable of relative warping movement within reasonable limits. When the tongue ends are moved inwardly toward each other from the position shown in Fig. 2 to their normal locking position shown in Fig. 1, the web 27 bends, forming a triangular projection which, in the assembled or looking position of the parts, enters a short distance through slot 24 into the container and is convex toward the container interior, engaging the upper edge of said slot at two points which. may be and commonly are fairly close to each other and centrally intermediate the slot ends. In effect, the deflected web 21 thus provides additional locking barb means intermediate barbs 33, This arrangement provides four separated bearing points 35 (Fig. 8) between the handle connecting tongue 23 and the upper margin of slot 24; and the spacing of these points may be varied to suit different types of material by varying the width of locking web 2'! and the extent to which such web is deflected. This extent is determined in the illustrated embodiment by the difference between the width of the tongue 23 adjacent barbs 33 and the distance between the ends of slot 24, the slot width being substantially less than the width of the handle at this point when in flat condition as shown in Fig. 3. Fig. 3 represents the position of each handle end or tongue after it has been pushed down wardly through the slot in collapsing the handle against or close to the top of the container body 25 to get it out of the way and enable stacking the packed containers one on top of another. Each handle tongue 23 most desirably narrows gradually away from barbs 33 until, at a point in the vicinity or the apex of triangular aperture 3 l, its width is not greater than the length of the transversely extending slot 24. By reason of the described construction, pulling the handle upwardly from its lower or collapsed position into the position shown in Figs. 1 and 4 automatically causes the broader portion of the tongue 23 to be contracted by the pressure of the slot ends on the edges 34, thereby deflecting web 21 out of the plane of tongue sections 32 into locking position.

The arrangement shown in Figs. 14 may be varied to facilitate assembly, assure retention of the locking web in operative position, or for other purposes. In the variation illustrated in Fig. 5, the slot 24a is provided with a widened central portion having an upper margin 35 substantially spaced from the lower margin 3'! of said slot, locking web 21a being elongated so that its angular upper edge will engage margin while the barbs 33 engage the upper edges of the slot ends in the manner already indicated. This structure provides additional room for insertion of the handle end in compressed condition as indicated in Fig. 6 and spaces the points of engagement of web 21a with the container body 25, in a direction transverse to slot Z ta, from the Zone of engagement of barbs 33 with said body.

Lower margin 31a of the slot 24a may be provided with a flange or projection 46 (Fig. 6) extending upwardly into the recess formed by the deflected upper margin 36, but desirably spaced 1 from said upper margin to provide room for the insertion of the tongue end with the locking web in deflected position as indicated in Fig. 7. Flange 46 is sufliciently wide to bear against the outer faces .of the legs 32 of the handle end at opposite sides of the web and substantially above the ends of slot 25a, thereby tending to press the handle end inwardly and to hold it in operative position against the outer face of the container side 26.

In the specific embodiment of the invention illustrated in Figs. 6 and 7, the lower margins or edges of the locking web are inclined inwardly from lines 28 to line 29 so that when web 21a. is deflected inwardly the lower end of said web will form a sloping entrance portion readily inserted in the slot 24a as will be apparent from Fig. 7. The upper edges 30a of the web may likewise slope upwardly from lines 28 to line 29 to form acute angled recesses or notches 39 adjacent lines 23 adapted to engage the upper edge 36 of slot Z ta when the handle end 23 is in operative or carrying position. With this construction any outward stress on the handle adjacent end 23 which might tend to withdraw the upper edges of web 21a from engagement with the upper edge of slot 2% will be resisted by the engagement of notches 39 with the slot edge.

The method of assembling the parts has been generally indicated in the description thereof, and is illustrated in Fig. 7. The legs 32 of handle end 23 may be pressed toward each other with the fingers while grasping the handle, thereby contracting the width of the tongue sufficiently to permit inserting it into the cooperating receiving slot, at the same time deflecting the locking web into operative position. Such insertion is most easily accomplished when holding the compressed "or constricted tongue at a substantial angle to the plane of the container body adjacent slot 25, and thrusting it through the slot. Then, by swinging the tongue into flatwise engagement with the container body, the locking web, as well as barbs 33, may be brought into engagement with the upper edge of the slot by drawing the handle end upwardly. The process of compression and insertion of the handle end may be carried out in other ways, and may be accomplished with great rapidity and ease.

The handle shank 22 may be provided with means for reinforcing the handle and more comfortably accommodating the hand of the user. As indicated in Figs. 1 and 2, this may be accomplished by providing said handle shank 22 with integral flanges 40 which may be folded inwardly along bending lines 4| so as to extend along the top of the handle when in use. Flanges 40 preferably have a transverse depth approximately equal to half of the corresponding width of the handle, so that the adjacent margins of said flanges abut each other in operative position and form a neat upper facing for the handle shank 22. Transverse bending lines 42 may be provided between lines M to assure even bending of the handle and a smooth sightly surface appearance thereof. The end portions @301 flanges All may be tapered to provide a gradual change in stifiness of the handle at these points, and thereby avoid a tendency to crack the handle transversely when it is bent adjacent the ends of flanges 40.

While the constructions described and illustrated are arranged to provide four bearing points along a single slot or aperture in the container body, the invention is not necessarily restricted to employment of a single slot, .or otherwise to the precise construction shown. Another arrangement providing four bearing points with a unitary tongue engaging at least two slots is illustrated in Fig. 9. In this specific construction, the container end wall 26 is provided with transversely extending slots 24b and 24c arranged in series extending longitudinally relative to the handle tongue, the sections 32a of which pass through said slots s eriatim and are provided on' their non-adjacent edges with multiple locking means, such as barbs 33a, 33b, engaged in the ends of said slots.

The described arrangement may conveniently be constructed to permit the handle end 23 to be moved downwardly through slots 2% and 260, for the purpose of collapsing the handle or for other reasons. For this operation the distance between the outer margins of legs 32a in the portion of the handle which slides through slots 2% and 260 is not greater than the transverse length of said slots and advantageously is sub stantially the same as said length. Moreover, the depth of bars 33a between said slots is substantially less than the distance between the slots, the difference between said depth and distance determining the extent to which the handle end 23 may be shifted downwardly through the slots.

The handle end 23 may be passed through an additional slot 24d located above slot 24b. This arrangement serves to locate the lower end of the tongue at the inside of the side member 26, protecting it against injury and permitting its retention in flat position by pressure of the merchandise. It also substantially increases the strength of the connection through frictional engagement between the handle end 23 and portions of the container body above slot 24?), due to outward pressure of the merchandise and inward pressure of the handle during use. Moreover, the portion of the container body 25 in which slot 24d is located may advantageously be at an angle to the container side 28, producing a neat type of tongue and slot connection at the junction between two sides of a container and improving not only the even curvature of the handle but also its frictional engagement with the portions of the container body 25 adjacent slot 24d.

In this construction (Fig. 9), the slit or cut 31a, is provided to divide the handle tongue longitudinally into sections or sub-tongues 3211 with free or unconnected ends. These sections are sufficiently movable relatively to each other to permit shifting them out of edge-to-edge register and overlapping them somewhat, thereby constricting the tongue as a whole to such extent as may be necessary to permit barbs 33a, 33b, to pass through the slots when assembling the parts. After assembly is complete, the resiliency of the sheet material causes the tongue sections to resume their normal flat edge-to-edge relation, with the barbs extending laterally beyond the ends of slots 24b, 240, in looking position, all as shown in Fig. 9.

Fig. illustrates another form which the tongue and slot connection of the invention may desirably take in practice. In this construction also the tongue is divided longitudinally into two sections or sub-tongues 32b, the shanks of which are spaced apart and the locking ends of which are free or unconnected with each other and adapted to engage in separate slots. In this instance, such division is eifected by elongated aperture 3ib, the length of which should be suflicient to permit collapsing of the handle down upon the top of the container. Each of the sections or sub-tongues 32b is provided at its free end with locking projections or barbs 33c and 21b, and the lower extremities of the sections are desirably rounded or pointed, as indicated at 45, for easy entry into the locking apertures Me which are separate from each other and somewhat spaced apart, as shown, for separate looking engagement by the respective tongue sections. In this construction, the upper edge 36a of each looking aperture is somewhat longer than the width of each section 3% above the barbs, but is somewhat shorter than the over-all width of the section at the barbs. These bars, when in normal locking position, i. e. when the handle tongue is in its uppermost position as shown in Fig. 10, therefore extend laterally beyond the ends of the edge a. In order to permit assembling the handle tongue with the container, it is accordingly necessary to so shape each aperture 24a as to render available, in some reasonably possible position of the tongue sections, an opening of sufficiently long dimension to receive the cooperating barbed section end, thereby permitting said ends to be thrust through the said apertures so that they can then assume the locking position shown in Fig. 10. And for most rapid assembling, the arrangement should be such that the two barbed ends can be thus thrust into position simultaneously. A satisfactory way of achieving this is to give apertures Me a sufiicient depth or extent below their upper edges 38a. An especially efiective arrangement is that illustrated, wherein the apertures are roughly triangular in shape, each with a vertical side edge 44, and inclined lower edge 31a making an angle of approximately 45 with the other two edges, the apertures being symmetrically disposed, as shown, with the lower inclined edges adjacent and divergent downwardly. Each of the inclined lower edges 31a of the apertures should have a length at least as great as the aforesaid over-all width of the cooperating tongue section at the barbs.

With this arrangement, assembling the handle with the container body may be effected very easily and rapidly. Thus, the operator, grasping the handle end 23 in one hand, may bend or warp it about a longitudinal axis by pressing the outside edges of legs 3221 between a thumb and finger, and causing the upper surfaces of these legs to incline or tilt toward each other. In this way thebarbed ends of the legs or sub-tongues may be brought into proper registry with the respective apertures 26c, with the pointed lower ends 45 directed at a substantial angle to the body section 26 and by then thrusting the barbed tongue ends into the apertures while bearing against thedownwardly diverging edges 31a of the apertures as guides, insertion of both such tongues into said apertures may be completely effected in one thrusting movement, whereupon releasing the hand pressure on legs 32b will permit them to spring back into their normal plane, with barbs 33c and 27b locked in the apertures against accidental removal regardless of the position of the handle end. The bending or Warping method of assembly involves no damaging distortion of the handle end.

The Width of sheet material left between apertures 246 should be suflicient to obviate any danger of transverse rupture of the sheet material of body section 26 by the pull of the handle end. Employing two apertures thus spaced apart by an intervening width of sheet material, instead of employing a single slot or aperture of equivalent total width transverse to the handle leads to a further very important advantage. When a single wide slot is employed, there is a tendency for the lower edge of the slot to spring out or gap open to some extent, thus presenting a projection which is likely to be hit or caught when, for example, something else is slid down along the end of the package, with the result that the material of the body section 26 may be sheared or torn starting at the lower edge of the slot. Where two apertures of relatively short transverse extent are employed, however, the intervening strip of sheet material thus left uncut serves to prevent such springing out or gaping and to hold the edges of both slots substantially flush with the body section 2%, thus eliminating the objectionable springing out or gaping above referred to.

It will be seen that in each of the several specific embodiments of the invention hereinbei'ore disclosed, the longitudinal cut or elongated aperture dividing or bifurcating the tongued end extends back toward the shank or grasping portion of the handle, from the locking barbs, a sufiicient distance to render easy the temporary contraction of the over-all width of the locking tongue as a Whole when inserting it into the cooperating slotting of the container body.

While the invention serves to strengthen both members of the tongue and slot connection structure at the points of engagement, it has been found that with the specific constructions described and illustrated it is possible to reduce to an exceptional extent the quality and therefore the cost of the container body or other slotcontaining member, and that the most eflicient balance between tongue strength and slot strength may be provided by employing for the tongue a type of material somewhat stronger than that used for the slot-containing member. This permits further reduction in cost of the entire structure, since the container body or the like ordinarily contains many times the quantity of material included in the handle or other tongue portion. It is to be understood however that this arrangement depends to a substantial extent upon the precise construction of the interengaging parts and that the invention may be incorporated in designs employing material of the same type for both parts, or even the use of stronger material for the slot-containing member.

While the preferred form of the invention has been described and illustrated in several embodiments thereof, this disclosure is intended to be illustrative and not restrictive, since the invention may be incorporated in other embodiments within the scope of the claims. Although reference has been made to paperboard as a material suitable for use in structures incorporating the invention, other types of relatively stiff, flexible sheet material, and particularly fibrous sheet material made principally from wood pulp and the like may be employed, the type selected depending upon the widely varying characteristics of the merchandise and the use to which the container and package are subjected. For instance, sheet materials of the types known as boxboard, pasteboard and cardboard may be used, as well as laminated structures, including surfacing layers of special fiber for improving appearance, printing qualities, resistance to moisture and the like, and also composite sheets of Kraft or other types of paper. The material may be impregnated to improve its strength, waterproof qualities and the like.

The bending lines referred to in the description may be of various types generally recognized as suitable to facilitate accurate and uniform bending of sheet material along a selected line, such forms including creases in which material is deflected along the line to form a trough on one side and ordinarily a ridge on the opposite side;

cut scores in which the material is partly severed along the bending lines; and other known constructions. The cooperating portions of the two connected members have likewise been referred to herein as a tongue and a slot owing to the general employment of these terms to describe the type involved herein; but these terms are not intended to be restrictive, the tongue being understood as including generally portions of a sheet member which are adapted to extend through a slot for retention in predetermined position, and the slot in the broader phase of the invention includes slits and apertures which may vary substantially in conformation but which are adapted to receive and retain tongues.

What is claimed is:

1. A separable connection construction for sheet material containers and the like comprising a sheet material member provided with a slot, and a laterally barbed sheet material tongue extending through the slot and in locking engagement with opposite ends thereof, the tongue including a portion located intermediate the side edges of the tongue deflected out of the plane thereof and in retaining engagement with a man gin of the slot.

2. A construction as set forth in claim 1 in which the deflected portion comprises a convex web having a margin in retaining engagement with the slot margin at two spaced points.

3. A separable handle connection construction for sheet material containers and the like, permitting longitudinal movement of the handle relative to the container between carrying and collapsed positions, comprising a sheet material member provided with a slot, and a sheet material tongue extending through the slot, the end portion of the tongue comprising two spaced lateral sections and a Web integral with and connecting the sections and deflected relative to the plane of said sections, with a margin of the web in retaining engagement with a margin of the slot, said tongue having an over-all width at the locality of said web, when the latter is undefiected, greater than the effective length of said slot but narrowing inwardly from said 10- cality to an over-all width less than said effective length.

4. In a handle connection construction for containers, the combination, with a container body formed of stiff flexible sheet material provided with a slotted zone, of a handle member formed of similar material and capable of longitudinal movement relative to the container body between carrying and collapsed positions without disconnection from said body, said handle member having an end portion longitudinally divided to provide a bifurcated locking tongue comprising tongue sections arranged and functioning in substantially one plane, passing through and longitudinally slidable in the slotting providedin said zone, said tongue sections being provided with a plurality of pairs of locking barbs each in retaining engagement with an edge of said slotting when the handle member is in carrying position; the bifurcation of said locking tongue extending back for some distance from said barbs toward the shank or grasping portion of the handle member, and said tongue sections being capable of movement relative one to another for temporarily contracting the width of said locking tongue as a whole to facilitate insertion thereof into such slotting.

5. A construction as set forth in claim 4 in which said slotted zone is provided with two slots through which the tongue sections respectively pass, and said tongue sections have free ends spaced apart a distance corresponding approximately to the spacing of said slots and formed for interlocking engagement'with said slots.

6. A construction as set forth in claim 4 in which said tongue sections are laterally spaced apart, and said slotted zone is provided with a plurality of slots each receiving one section of the tongue, each of said sections having locking provision at both lateral edges in retaining engagement with the margin of a slot.

7. A separable handle connection construction for sheet material containers and the like, permitting longitudinal movement of the handle relative to the container between carrying and collapsed positions, comprising a tongue formed from a single piece of sheet material and divided longitudinally into two spaced sections of substantially equal length, each having a free end barbed on both edges, in combination with a sheet material container member provided with a pair of spaced locking apertures arranged side by side and having locking edges extending transversely of the tongue sections, said apertures having a sufiicient depth away from said locking edges to permit simultaneous insertion of said tongue sections, and said tongue sections being longitudinally slidable within said slots a distance suflicient to permit collapsing the handle toward the container from carrying position.

8. A construction as set forth in claim 4 in which the slot through which one tongue section is slidable is in spaced and aligned relation with the slot in which another tongue section is slidable, said slots extending transversely of the handle.

ERNEST M. BROGDEN. 

